Motor-control system.



@onpas/bjr ld INVENTOR n WI'TNESVSES. Wlliam,IiPqm'aTl AT TORNEY y lUNITED STATES PATENT OFFICE. Y \.\`IIJLIAM H. POWELL, Oh NORWOODfOHO; ASS-,IGNOR TO ALLISCHALMERS COMPANY, A CORPORATIO OF NEW JERSEY, AND THE BULLOCK ELECTRIC MANUFACTURING COM- PANY, A CORPORATION OF OHIO.

xoronoonrsoa srs'ssm.

To 4all whom it may concern:

.Be it known that I, WrLLrAM H. POWELL, a citizen of the United States, residing at Norwood, in the county of Hamilton and State of Ohio, have invented certain 5 new and useful Improvements in Motor-Control Sys-V tems, 'of which the following is a full, clear, and exact vspecification. y

My invention relates to control systems and particularly to control systems for mills' and hoisting motors. l0

necessary that the moving parts be quickly and often reversed. Heretofore, steam engines have generally been used for this work. Certain electrical systems for doing the samework have been proposed by others, but these have generally been unsatisfactory.

In my cope'nding applications Serial Nos. 311,827; 324,126; and 328,047, filed April 16, 1906', June 30, 1906, 4 and July 27, 1906, respectively, I have illustrated and described systems inA which a great inany of the dif-iiculties of these prior electrical systems have been overcome'. In all of these co-pending applications, systems have been described in which the working motor is supplied with current by a special generator' on whose shaft is a ily-wheel, there being a single controlling arm l which varies inversely the field resistances of the working motor and the special generator. ,I My present invention is intended to-obtain the same result as is obtained in the system described in lmy copending applications, viz.,` obtaining'an inverse variation oi the field strengths of the working motor and the 'special generator, but does this without necessitating the 'rise oa variable resistance in the working motor I field circuiti Yln'oneiasp ct y invention consists of a motor conj n trl system cbmpr'ising a motor, a source 'of current for lsupplying'oneiofithe"motor field windings, a second Asource of currentfo supplying another ofthe motor field windings" and the motor-armature, and means for aryin'gt v lctrinnot'iv'ei force of said second source v motor supplie l eby; affiy-whel mechanically connected to sa" l `"noter, ai generatorfdrivenby said` motor, a5 a second niotni-'havingmain andopposing field windings whose armature and opposing field windings are supplied by said generator, a separate source of supply for the field findings of said second motor, and means for varying and reversing the field of said generator. l

Other features o my invention will appear Afrom the following description and accompanying drawings and will be particularly pointed vout in the claims.

In rolling mills and -in hoisting machinery it isv aspectf'my invention consists of a. r'trol comprising aisource of current, a

lpeoioation of Letters Patent. application and July so. 19de. sesam. 929,326.

`The motor D may bevueed to drive any desired ma- 'The controller H is also arranged to reverse the current Patented Sept. 10, 190".

The single figure ofthe drawings shows one embodiment of my invention.

In this figure A is an electric motor of the three-phase. induction type, though obviously other forms of motors could be used instead. In the rotor circuit of this motor is a starting resistance `1 adjustablerby means of a short-circuiting bar 2, and a regulating resistance 3 arranged 'to be cut in and out by a solenoid switch 4, which in turn is responsive to the current strength in the primaryI circuit of the motor asthrough a series transformer 5. Other means for varying they speed of' motor A may be used if desired. A generator armature B is driven by the motor A, being preferably directly connected thereto, and on the common shaft of the motor A and the generator B is a heavy ywheel C. The generator B supplies current to the armature D and an opposing ei d winding d of the working motor.

chinery. .l l i The field windings b of the generator B and the main field windings a" of the working motor D are sup- `plied'iro1n any direct current source through a switch 6. The strength of the field coil d is-usu'ally kept' constant but may be adjusted by a rheostat 16. The ield'coil b is controlled by' the main'controller H, which is arranged to vary theresistance .in circuit with this field coil and to reverse the cuncnt therethrough. `80 in the opposing shunt field' coil d2 of the working motor.. The arm or handle h of this'controller is divided into several electrically distinct parts as shovm. The

-lower part of the controller H varies and reverses the current in the generator field coil b while the upper` part reverses the connections ofthe opposing field coil d2 oi the Working motor. There` are shown 'two variable resistances 14 and l5 forithe generator field coil, but if desired instead of havingthese resistances sep' arate the contacts of one may he connected to the cor- 'responding contacts of the other, one of the resistances being omitted. n

The controller is arranged so that when its arm h is moved on lone side of the vertical the. resistance' 14 is varied to 4control the speed of the motorv DA in one direction, vandgwhen moved on the other side of the vertical resistance l5 is varied to control the motor D in'the other direction, the` direction of current through the coil b being reversed vas the arm h passes through its vertical'or oli4 position. As the farm h passes through its vertical position it also reverses the conne'ctions of the shunt field coil d of the workingmotor, but this is not for the purpose of reversing the current through this coil but in order to maintain the current I coil ll, may beconnected across the or taking up the field discharge of the latter.

A non-inductiveres'istance 13 is connected inseries being kept the same, the-time constant 3.5 by moving the bar2 starting. After the motor therethrough in the same direction; for by reversing the current in coil b, the current supplied by armature B is also reversed. Between the segments '1: and 8 of the controller is arranged a resistance? to take up 5 the generator field discharge when the circuit through the coil b is broken. A similar resistance could bo used if desired to take up the discharge o thecoil d2,

but this is generally unnecessary because this field coil can discharge through the armatures B and -D.

1.0.'l`he resistance 9 is laided in taking up the iield discharge of coil-b by a high resistance ll permanently cbnnected across the coil vb. A similar high .resist ance lla, identical in purpose and operation with the 'l d2 to assist in with the field coil B. This resistanee'has an .ohm'rc value several times as great as that `oi the field coil with which it is in series. The purpose of this resist- 20 ance is to diminishlthe timeconstant oi the field mag- If desired, a similar resistance. 13 may be'placed the circuit oi theopposing coil 1P of the working motor,y

30 in 'order to reduce the time constant of' said eld coil,

although the current in this circuit is never reversed but'only varied in strength and interrupted. The operation of the'system'is as followsz--The primary circuit of motor A is closed and the motor started to cut out the starting resistance l. The switch' 4 isheld onen-.by its solenoid at vthis time because o the heavy current required for starting the motdr, but if desired other means may be used to insure the open' 'condition4 oi this switch during has gained sufficient speed and the starting resistance has been cut out, the solenoid switch is allowed to close' to cut out resistance 3 because of the decrease in the primary current of motor, v A. The fly-wheel C and generator armature-,AB arealso '45 Asta'.rted.ivith' the motor A and the fiy-wh'eel storesmechancal energy by its rotation. During this starting the arm his preferably in its vertical or off posi-l tion. The switch 6 now being closed, the iield of the Workingmotor is at its strongest for the opposing field coil d2 is denergized and the -constant main field coil `df is not v'veakened thereby; 'llhe generator field coil b is denergized. The arm h is now gradually moved I* from the vertical to thev horizontal in the proper direc- `tion toy give the motor D the desired direction oi rotation. As this ann moves, say clock-wise, itLfirst connects lthe lcoil' d? across armature B though at this time that armuture is supplying no current. Next the circuit ofthe generator field coil b is closed through the lwhole resistance l5 and said resistance is gradually cut 50 out o circuit. As `this resistance is cut out the strength oi field coil b graduallyinc'reases, thus correspondingly increasing the electromotive force impressed on the arma ture D and the opposingfield coil d2 of the working motor,

the latter by increasing in strength causing the resultant total field ofl saidmotor to decreasein strength. Thus the speed oi 'motor D is increased, both becausethc l electromotive force impressed upon it is increased and because its field strength is decreased. The speed which the motor D acquires depends upon the extent vmotor to slowr down, thus allowing the ily-Wheel C to give up some oi the mechanical energy it has stored, which energy helps the motor A to drive generator B to supply electrical energy at the rate demanded by the motor D to drive its loadz I I i, K

As the arm h is moved backward toward the vertical, the field d is weakened' to decrease the electromotive force ofl armature B. This decreases the speedl oi motor D because of the; decrease in the electromotive .force impressed on itsarmature and also because of the increase in its total field strength dueto the decrease in the strength of the opposing shunt field coil 'd and causes it to act as a generator to supply current to the armature B, the latter nowserving as a motor powerful braking effect on the Working motor-due to its acting as a generator. the primary oi transformer 5 also causes the solenoid Asothat the latter may also supply energy to the fiy- Wheel C. The fly-Wheel thus stores up any excess of lenergy supplied when the rate of such supply exceeds the rate at which energy is demanded by the working rate vat Which energy is demanded by the i working motor is greater than the rate at which energy is supplied. When the arm h leaves the contacts of resistance l5, and slides over the segments 7 and 8, the resistance 9 is connected in circuit with the coil b Le take the field discharge therefrom, the resistances 1l and lf3 .assisting in this. After the field coil b is disconnected motor is also' broken. When the arm h is moved inthe other direction from the vertical the above cycle is repeated save that the working motor D iscaused to roinstead'of th 'e resistancel5. Y

With my invention it is possible to quickly ,reverse motors especially those of largefcapacity this with a veryl small waste of energy. possible to diminish the carrying capacity of the mains formity with which energy is demanded ortliis motor.

voltage are demanded by theworking motor at nearly necessary to point out y as they-Will be-obvious to one rskilled in' the art.`

of movement of the arm h, the iull speed being reached.

.thecircuit o the opposing shunt coil d2 of the WorkingA tate in the other direction and the resistance 14 is usedV and do It isl also" which supply the'motor Al because of the great uni'- The capacity of machines B and D can also be greatly reduced because the maximum current and maximum the same time. Another advantage ofpmy invention.

This increases the slip of motor A and permits said to help restore energy to theily-wheel C. There is a The diminished current in.

switch-4 to close, thereby increasing the speed oi motor motor, and givesup said stored energy-whenever the l o my invention which it is not' sessie When -I'use the term inversely in this ldescrip- 'on and in the claims, I do not wish to limtmyselijto et inverse 'proportion 7, but intend the term to include any increase in one and decrease in the othr lfoffth'e two things specified. A I have described myin'vention inwhat I now concider-to be-its preferred form, but I aim tocyer all i those obvious modifications which readily occur to skilled in the art.

Having thus described my invention, what I claim as new and desire to secure by, Letters Patent ist-- 1.'A system ofviotorlcontrol, comprising a motor hav-- 'ing aimain field and an opposing field, a generator for'sup` plying the armature of s aid motor, a separate.source fort' vsupplying the main tieldwinding of the motor, and means for varyingthe eleetromotive force of the generator and the' total iieldstrength of the'motor.

. A 2.-'"A systern of motor control, comprising a motor'havfing a main field and an opposing field, ageneratr for supplying the armature of said motor, a separate source for supplying the main field vvinding of the `motor,-'and means-for varying the electromotive force of the genera- 4 ytor and the tot`al iield rstrength of the motor inversely.

3. A system of motor control, comprising a motor having main and opposing iield windings, a generator for supplying the armature of the motor, a separate source of u'rrent for supplying the main field winding of tlie motor, and means for varying the electromotive force of theV generator and. tl1`e"strength` of. current in the opposing f7 field winding ot the motor.

4. A; system of motor control, comprising a motor having main and opposing' tield windings, a generator for s upplying'thearmature of the motor, a separate source of current for supplying the mainfleld winding of the motor, andineans for varying the electromotive force of t e generator and the strength of current in the .opposingiield windingof the motor correspondingly.

, 5. A system of motor control, comprising a motor ha ingmain and auxiliary field windings, 'a generator Iorsupplylngthe armature of said motor, a separate source of current for supplying one of the iield windings of themotor, and a singlemeansfer varying the ield strengths of thegeneratorand themotor. u "56. A systemof motorcontrol, .comprising Aa motor having main and auxiliary windings, a generator tor-supplying the armature of said motor, a separate source of cur-A rent'tor supplyingone of the eld windings ofthe motor, Y'and a 'single means for varying -the field strengths ot the generator and the motor inversely. l 7. A- system of motor control, 'comprlsinga` niotorJav-l ing main and :auxiliary deld windings, a generator 'for :sup-' pl'ying thev armature and auxiliary iield'windingmf the. motor, 'a separate source of current for supplying Athe vmain vfield winding -ot the'motor, and means tor-.varying` the yelectroxnoiive force ofthe generator. l

' 8.-.A system ot motor-control comprising ing main and auxiliary iield windings, a-generatortorsup :p'lyln'g the armature andauxiliary deld winding of the motor, a separate sourcepf current rorsupplying the main liield winding of the'rngton and means ior' varying and reversing theelectromotive force-oi! the generator.l y. s

39. A `systemot motor controlcorprislnga motor hav ing main andauxiliaryiield windings, a'generator for sup- 'plylng the armature and yauxiliary field winding of the v* motor, `a separate source of current for supplying the main field-winding of themiitor, .and lmeans tor varying the iield of the generator. 1

10. A system ofmotor controL-comprising a motor having main and'auxiliary iield windings, agenera-tor vi'or supplying the armature4 and auxiliary field winding of the motor, a separate 'source' oi! current foisupplying 'the main ileld winding ot themotor, and meanstor nryivngfand reversing the neld o! the generator. '/'1 j 11. A system ot motor control, comprising a :new: havlng main and' opposingnelvindings, a. generator for sup'- plylngthe armature Isdn-opposing .deld winding ot the motor, a separate source-ot, currgnt for supplyingjthqmdin l a motor havoneA tromotive force' of the generator, 12. A system of motor control, comprising a motor hav- 'field winding otthe motor, and means fior varying the elecing malnra'nd opposing eld windings, a generator for supplyingthe armature and opposing iield winding of the motor,` a separate'source of current for supplying the main iieldwinding of the'-,motor,'and means fr varying and l'reversing the-electromotive force of the generator.

13. A system of motor control, comprising a mptor hav ing main and opposing iield windings, a generator for supplying the armature and opposing field 'winding of the motor', a separate source of current for supplying the'main field winding ofthe motor, and means for varying the iield of tire-generator.v

'5214'. is system ot`motor control, comprising a motor liavA ing main and opposing ield. windings, a generator for sup 4plying the armatureand opposing field winding of the motor, aseparate source otfc'urrent for supplying the main iield winding of the motor, and means for varying and reversing the eld of the generator. 15. 'A-system of motor control, comprising a motor having a; separately excited main field ancla shunt opposing ileld, a generator for supplying the armature and shunt iield of the motor, and means for varying the electromotive force of said generator.

16. A system of motor control, comprising a motor llavinga separately excited main eld and a shunt opposing eld, a'geuerator for supplying the armatureand shunt field 'ofjthe motor, and means for varying and reversing the ele'ctreinotive torce of said generator.

17. A' system of motor control, comprising a motor havv-iiig a separatelyexclted main field and shunt opposingl deld, a generator for supplying the armature 'and shunt field of the motor;y and meansffor'varying the iield of said generator.

18;,'Afsystem ot motor control, comprising a motor having'a separately excited main Jiield and a shunt opposing ileld,r a generator tor supplylngjhe'armature and shunt field of the' motor, and means for varying and reversing the iield of the generator. l

19. `A system of motor control, comprising a motor having `a separately excitedmain iield and a shunt opposing ileld, a genera/tor for supplying the 'armature and shunt iield otthemotor, land means for varying and reversing the elecfromotlvegoree of the generator and for-reversing the connections off-the motor shunt fleld. Y

'20. vA syatentt of motor control, comprising a motor havlng a separatelyexcited mainiield and a shunt opposing deld, a generator tor supplying the armature and shunt d eldl ofithe motor, and' means for varying and reversing ythegenerator ileld and for;reversing the Vconnections of the motor shunt iield. r v

21'. llaa system of motor control, comprlslug'a dynamoelectric generator driven by a source of substantially constapt power, a combined lsluint and separately excited motorsupplied by the generator, menus for varying the electromotive torce of the generator, 4and means for mevclianically storing any excess of the energy supplied by the driving source and supplying said stored energy to the motor whenever required.

. to the' generatgr when its rate of supply exceeds the power Y. demanded by the motor at' that time, and means for causfing wld 4stored energy tube supplied to the motor whenaveathepower demanded by the motor is above that normolly supplied. lj

424. "A motor eontrol`. system, comprising a source of cubatura'tially constant mechanical power. p. gener-atom driven thereby, a variably, loaded -combined shunt and 'ing .field winding supplied by said excited -motqr 'whose armature and shunt eld uinding are supplied by the generator, a separate source rf current whichsupplies the main field winding of the motor, meansfor varying the electromotive force ofthe generator. means for storing any excess of the mechanical energy supplied hy the source when iis rate of supply exceedsthe ral at which energy is demanded hy the load 'on the'motor, and means for causing; said stored energy tolle supplied to the motor as electrical energy 'when energy is demanded by the load at a rate which exceeds the normal rate at which the mechanical-energy is sup-- pliell. v y

25. A motor control` system, comprising a motor having; main and opposing field windings, means for inversely' varying its total field strength and the electr-omotive force impressed uponits armature, means for mechanicallyv storing any excess of energy when the`supplied power exceeds the pow'er demanded by the motor load, and means tor causing said stored energy to be supplied 'tothe motor as electrical energy` the power demanded hy the motoiload exceeds the'supplied power.

.-26. In immbinatiomfa source of power, a generator' driven-thereby, a motor whose armature and shunt field are supplied 'byth'e generator, a separately excited main deld for the motor, means tot varying the field strength et the generatorf'af -ily-wheel on the shaft ot the power source, and means -for'causlng the iiy-wheei to give up its separately energywhen the loadon the motor rises above normal.

A i, Alu combination, a source of power, a generator `v driven thereby. a motor'having an armature and an opposgenerator and a main 4field winding'suppliedfrom a separate source, means for varying the resistance in the field circuit of the generator.

` a fly-Wheel oxi`the "generator shaft, and means for allowing said ily-wheel to giveup its energy when the motor load I rises above normal.

Nture and one of the field windings of said motor, a fiy- .wheel mechanically connected to said generator, means for varying theeld strength of the generator'to vary the field strength and impressed electromotive force on the armature of the working motor,.and means for causing the generator to run slower when the motor load is heavy than when the motor load is light.

31. In-combination, a motor having a constant field and a variable iield, a generator for supplying the armature of said motor, and means for varying the generator field and the variable field of the motor.

32. In combination, a motor having a constant iield and` `2 8.y A system of motor control, comprising a motor havinginain and auxiliary field windings, a generator supplying said motor, a iiywheel on the shaft ot' said generator,

-andmeans'for inversely varying the field strengths of said generator and-said motor. f

:29. A system of motor control, comprising a motor havA ing shunt and separately excited held windings, a generator supplying the armature and shunt winding of said motor, a y-wheei mechanically connected tol said generator, meansA for permitting the fly-wheel to give up its energy wheneverthe load outhe motor exceeds ja predetermined value, 'and a controller for varyingr the field strength of the generator to vary the speed of. the motor and to cause ener'gy to he restored to the fly-wheel while the motor is being retarded.

30.' In a system otmtor control, a motor having a plurality of field windings, a generator supplying the armi.

and reversing the field .the connections of the said motor, and means for varying of the generator and for reversing variable field of the motor.

33. In combination, a motor. having a constant eld and an opposing variable held," a generator for supplying: the armature of said motor, and means for varying the generator field and the variable field of the motor.

34. In combination, a motor having a constant field and sn opposing variable field, a generator for supplying the field windingof constant strength and by the generator, means for armature of said motor, and means for varying and reveriopposing field wlndingot the motor, and means for varyf ing and reversing 3T. In combination, a motor having a main field wind,-4 ing of constant strength and an opposing field winding of .variable strength, agenerator supplying the armature and opposing field winding of the motor, and means for varying the electromotive torce of the generator.)

and reversing the electromotive torce of the generator yand y for reversing the connections of the opposing field of the motor.

38. In combination, a motor having a separately excited an opposing shunt field winding ofvarlable strength, a generator supplying the armature and shunt winding of.' the motor, and means for va/rying the field strength of the generator.

39. In combination, a motor having a separately excited field winding ot constant strength and an opposing shunt field winding of variable strength, a generator supplying the armature and shunt winding of the motor, and means for varying and reversing the field ot the generator.

40. In combination, a motor having a separately excited field winding of constant strength and an opposing field wndingXptvariable strength, a generator supplying the armature and opposing' field winding of said motor, and means for varying and reversing winding of the motor..A l

41. A system of motor control, comprising a 'generator'. a combined shunt and separately excited motor supplied varying the held-strength o t the generator, and a resistance permanently in the generator field circuit.

42. A system of motor control, comprisinga `generator, a combined shunt and separately excited motor supplied by the generator, means for varying the field strength o! the generator, and a resistance permanently in theY moto!" shunt field circuit.

the field of the generator and for reversing'the connections ofthe opposing field` 43. A system of motor control, comprising@ generator. I

a combined shunt and separately excited `motor supplied by the generator, means for var ,ing the field strength ot .the generator, and resistances permanently-in the .generator field circuit and the motor shunt eld circuit respectively.

44. A system ot motor'control, comprising a generators',

a combined shunt and separately excited,motor supplied thereby, means for varying and reversing the'generator field, anda high resistance connected.acrossthegenerator eld. terminals.

45. A system of a combinedshunt and sepamtelyexcii motor supplied thereby, means-for varying and reversing theeld o! the generator and` for`reversing the'connections offthe motor shunt field, yaai-da 'high'resistnce connected 'across motorshunt field. x

46. A systemot'motor control1 comprising .a generator; a combined shuntnndseparately excited motor supplied thereby, meansfor varying and reversingl the ^Ifield of the generatonandror reversing the connections of the motor shunt field, and high resistances connected across the gem erator eld and the motor-shunt field respectively. -In testimony whereof I adix my'slgnature, in the presence of tivo witnesses. WILLIAM H. POWELL.

Witnesses Gno.- B. ScHLnx, Fano I. Isxusnr.

motorcontrol, comprising a gcneraten' Correction in L'ettr' Palen't-No. ll.

It -is liereby certied that in `Letters Patet N o. 865316, granted September 10,` 1.907',

uponv. the application of William H. Powell, of Norwood, Ohio, for ah improvement in y Motor-Control Systems, an error appears in the prinfed specification requiring vcorreotion, as follows: In 1ine'1`30, page 3, th word In sh'ould be stricken out;` and that the said Letters Patent should berea'dwith this corre'ction therein A.that-f the same may conform to the recorfil'of tho oase in tl1 Patont Oioe.

signed and' samedi-,his 29th day of october, A. D., 1907.'4 o l l [SEAL] E. B. MOORE,

Commissioner of Patents. 

